This proposal requests continued support for an Epidemiological Research Program as a major component of the University of Southern California Comprehensive Cancer Center. The professional staff of the Program consists of 10 epidemiologists and statistician whose primary emphasis is on the development and conduct of studies concerned with iatrogenic causes of cancer. The scientific Program of this proposal consists of 6 case-control studies on this theme. They include the following: (1) A case-control study of the relationship between age-specific use of oral contraceptives and breast caner risk in young women. This study attempts to improve methologically on previous studies of this hypothesis; (2) A case-control study of the relationship between cyclic estrogen-progestogen therapy and breast cancer risk in post menopausal women. Estrogen- progestogen therapy is a recent and increasingly popular alternative therapy to "unopposed" estrogen therapy; (3) A case- control study of age-specific use of oral contraceptives and adenocrinoma of the cervix in young women. Incidence rates of adenocarcinoma of the crevix in women under age 35 have increased 8% per year in LA during the past decade; (4) A case- control study of long-term use of analgesics and diuretics in the etiology of cancers of the bladder and kidney. The former exposure, in particular, has been associated with cancer of the renal pelvis and there is some evidence to believe that it may also be related to other urinary tract tumors; (5) A case-control study of diagnostic and therapeutic radiation in the etiology of acute myelogenous leukemia. This highly fatal disease has been rapidly increasing in incidence and mortality nationwide; there is suggestive data for a role of low dose radiation exposure which may explain this increase; (6) A case-control study of a possible inverse relationship between spinal meningiomas and estrogen replacement therapy. Spinal meningiomas, like osteoporotic vertebral compression fractures, occur primarily in elderly women and involve the thoracic spine. We hypothesize that meningiomas result from fracture induced trauma to the meninges and that estrogens will lower risk by preventing osteoporosis. The major core resource of this program is the Cancer Surveillance Program (CSP) a population based tumor registry of Los Angeles County. Funding is requested for that portion of the registry involving active and rapid case ascertainment for the case-control studies described above.